Transparent conductive films containing thin metal wires have been studied as disclosed in US Patent Application Publication No. 2004/0229028, International Publication No. 2006/001461, etc.
Touch panels have attracted much attention in recent years. Though the touch panels has currently been used mainly in small devices such as PDAs (personal digital assistants) and mobile phones, it is expected to be used in large devices such as personal computer displays.
A conventional electrode for the touch panel is composed of ITO (indium tin oxide) and therefore has a high resistance. Thus, when the conventional electrode is used in the large device in the above future trend, the large-sized touch panel has a low current transfer rate between the electrodes, and thereby exhibits a low response speed (a long time between finger contact and touch position detection).
A large number of lattices made of thin wires of metal (thin metal wires) can be arranged to form an electrode with a lowered surface resistance. Touch panels using the electrode of the thin metal wires are known from Japanese Laid-Open Patent Publication No. 05-224818, U.S. Pat. No. 5,113,041, International Publication No. 1995/27334, US Patent Application Publication No. 2004/0239650, U.S. Pat. No. 7,202,859, International Publication No. 1997/18508, Japanese Laid-Open Patent Publication No. 2003-099185, etc.